What are historical examples of (alleged) miracles that were attested to by two or more (self-proclaimed) eyewitnesses?

Many Latter-day Saints experienced many miracles at the Kirtland Temple.

William Draper (account):

And there in the [Kirtland] temple on the Day of Pentecost of the 6th day of April 1836 there was such a time of the outpouring of the spirit of the Lord that my pen is inadequate to write it in full or my tongue to express it. But I will here say that the spirit was poured out and came like a mighty rushing wind and filled the house, that many that were present spoke in tongues and had visions and saw angels and prophesied, and had a general time of rejoicing such as had not been known in this generation.

Milo Anders (account):

The summer of 1835, I traveled in the state of New York with Nathan Baldwin, baptized several, and the following winter went to school in Kirtland, and in the spring of 1836, I was in Kirtland at the dedication of the temple and the endowment of the elders that the Lord had promised as a reward for their offerings. The blessings of the Lord were poured out abundantly. There is one thing that I would here relate, that was a great joy to me, and that was when the Holy Ghost was poured out on the elders, I saw fire descend and rest on the heads of the elders, and they spoke with tongues, and prophesied.

Joseph Smith, History of the Church, Vol 2(account)

...called upon the congregation to speak, and not to fear to prophesy good concerning the Saints, for if you prophesy the falling of these hills and the rising of the valleys, the downfall of the enemies of Zion and the rising of the kingdom of God, it shall come to pass. Do not quench the Spirit, for the first one that opens his mouth shall receive the Spirit of prophecy.

Brother George A. Smith arose and began to prophesy, when a noise was heard like the sound of a rushing mighty wind, which filled the Temple, and all the congregation simultaneously arose, being moved upon by an invisible power; many began to speak in tongues and prophesy; others saw glorious visions; and I beheld the Temple was filled with angels, which fact I declared to the congregation. The people of the neighborhood came running together (hearing an unusual sound within, and seeing a bright light like a pillar of fire resting upon the Temple), and were astonished at what was taking place

...The number of official members present on this occasion was four hundred and sixteen

Prescindia Huntington (source is a book-unread, may read differently, taken from this site)

In Kirtland we enjoyed many very great blessings, and often saw the power of God manifested. On one occasion I saw angels clothed in white walking upon the temple. It was during one of our monthly fast meetings, when the saints were in the temple worshiping. A little girl came to my door and in wonder called me out, exclaiming, 'The meeting is on the top of the meetinghouse!' I went to the door, and there I saw on the temple angels clothed in white covering the roof from end to end. They seemed to be walking to and fro; they appeared and disappeared. The third time they appeared and disappeared before I realized that they were not mortal men. Each time in a moment they vanished, and their reappearance was the same. This was in broad daylight, in the afternoon. A number of the children in Kirtland saw the same.

"When the brethren and sisters came home in the evening, they told of the power of God manifested in the temple that day, and of the prophesying and speaking in tongues. It was also said, in the interpretation of tongues, 'That the angels were resting down upon the house.'

"At another fast meeting I was in the temple with my sister Zina. The whole of the congregation were on their knees, praying vocally, for such was the custom at the close of these meetings when Father Smith presided; yet there was no confusion; the voices of the congregation mingled softly together. While the congregation was thus praying, we both heard, from one corner of the room above our heads, a choir of angels singing most beautifully. They were invisible to us, but myriads of angelic voices seemed to be united in singing some song of Zion, and their sweet harmony filled the temple of God.

Nancy Harlacher (same source as above? taken from the same site)

"We were also in the temple at the pentecost. In the morning Father Smith prayed for a pentecost, in opening the meeting. That day the power of God rested mightily upon the saints. There was poured out upon us abundantly the spirit of revelation, prophesy and tongues. The Holy Ghost filled the house; and along in the afternoon a noise was heard. It was the sound of a mighty rushing wind. But at first the congregation was startled, not knowing what it was. To many it seemed as though the roof was all in flames. Father Smith exclaimed, 'Is the house on fire?'

"'Do you not remember your prayer this morning, Father Smith?' inquired a brother.

"Then the patriarch, clasping his hands, exclaimed, 'The spirit of God, like a mighty rushing wind!'

"At another time a cousin of ours came to visit us at Kirtland. She wanted to go to one of the saints' fast meetings, to hear someone sing or speak in tongues, but she said she expected to have a hearty laugh. Accordingly we went with our cousin to the meeting, during which a Brother McCarter rose and sang a song of Zion in tongues; I arose and sang simultaneously with him the same tune and words, beginning and ending each verse in perfect unison, without varying a word. It was just as though we had sung it together a thousand times. After we came out of meeting, our cousin observed, 'Instead of laughing, I never felt so solemn in my life.

This answer is already quite long, can provide another answer with more miracles from LDS perspective if wanted.

_{All emphasis mine}

Some brief examples follow. All of these are God's working, not from any human being.

Be aware that simply googling many of these names will bring up critics like the Pharoah and his magicians who for selfish or unbelieving motivations desire to discredit them. Remember, that many Pharisees accused Jesus, Himself of casting out demons by the power of demons. Also, that they had Him crucified out of their own unbelief.

The documentary movie series by Darren Wilson, "Finger of God", "Father of Lights", "Furious Love", "Holy Ghost", Multiple documentaries, including miracles Sid Roth has a TV show, which frequently discusses modern day miracles.

A modern day example of this. I personally prayed for Mark Houser before his miracle. Briefly, he had partially inoperable, likely fatal, prostate cancer. The oncologist, who did not believe in Christ, could not explain when the inoperable portion miraculously disappeared two days before the surgery. He had posted a testimony of this on YouTube, but now I can't find it. The oncologist became a believer after the miracle and follow up conversations with Mark. It is written here. DuckDuckGo Search results but most likely because so many people believe it is a lie, I can no longer find it here. Same search on google or here youtube search despite the fact I used to share his testimony through youtube.

John G. Lake is famous for miraculous healings. "The healings that occurred under his ministry were documented thoroughly. ..." Unfortunately, he was before video recording was widely available. John G. Lake documented Many accounts say, researchers could put disease on his skin and watch the disease die. Bubonic plague died in his hand.

Smith Wigglesworth, was famous for miracles.

Todd White, a modern evangelist, has had many documented healings.

Bethel School of Supernatural Ministry in Redding California is known for miraculous healings.

Heidi Baker has multiple documented healings.

Kathryn Kuhlman also has documented healings.

Related note: The question as currently stated is not clear about LDS or a more general perspective. None of the people mentioned above agree with LDS theology.

The Azusa street revival may have some on video. Azusa street search